/* -*- c++ -*- */
/*
 * Copyright 2002 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 * 
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include <cmath>

#include <gri_goertzel.h>

gri_goertzel::gri_goertzel(int rate, int len, float freq)
{
  d_d1 = 0.0;
  d_d2 = 0.0;

  float w = 2.0*M_PI*freq/rate;
  d_wr = 2.0*std::cos(w);
  d_wi = std::sin(w);

  d_len = len;
  d_processed = 0;
}

gr_complex gri_goertzel::batch(float *in)
{
  d_d1 = 0.0;
  d_d2 = 0.0;

  for(int i = 0; i < d_len; i++)
    input(in[i]);

  return output();
}

void gri_goertzel::input(const float &input)
{
  float y = input + d_wr*d_d1 - d_d2;
  d_d2 = d_d1;
  d_d1 = y;
  d_processed++;
}

gr_complex gri_goertzel::output()
{
  gr_complex out((0.5*d_wr*d_d1-d_d2)/d_len, (d_wi*d_d1)/d_len);
  d_d1 = 0.0;
  d_d2 = 0.0;
  d_processed = 0;
  return out;
}
